Flash or Non-volatile memory (NVM) devices typically include a grid or an array of storage elements or cells, each including at least one NVM transistor and a number of peripheral circuits including decoders, drivers, sense amplifiers and control circuits to read from and write to the array. NVM transistors generally include a charge-trapping or charge storage layer, and require a high voltage (HV) in the range of four to ten volts for program and erase operations. The peripheral circuits include logic Field Effect Transistors (FETs), which typically operate at a low voltage, as well as a number of HVFETs capable of supporting the high voltages required by the NVM transistors.
It is becoming increasingly common to monolithically incorporate logic FETs and HVFETs on the same substrate as the memory cells to provide improved efficiency, security, functionality, and reliability. However, incorporating logic FETs and HVFETs on the same substrate along with the NVM transistors is challenging as each device or transistor typically requires different fabrication parameters.
Accordingly, there is a need for a semiconductor or NVM device integrating memory cells, HVFETs and logic FETs embedded or integrally formed on a single substrate, and methods for fabricating the same.